Do Humans Grow & Shed Hair Throughout Their Lifetimes?

Healthy humans grow and shed hair in a continuous cycle. According to the American Academy of Dermatology, shedding occurs after hair cells enter a dormant phase known as telogen.

Growth Cycle

• A typical hair growth cycle may last anywhere from two to six years, according to the American Academy of Dermatology. During that time, about 90 percent of a person's hair continues to grow while the remainder undergoes telogen. Hair grows approximately half an inch each month, although older people may experience a slower growth rate.

Normal Shedding

• After a hair rests in the telogen phase for up to three months, the scalp sheds it and a new hair grows in to replace it. The American Academy of Dermatology states that a human typically sheds between 50 and 100 hairs per day without any signs of thinning or baldness.

Hair Loss

• Certain illnesses or genetic factors can cause shedding to speed up until it outpaces regrowth, resulting in thinning hair or baldness. Immune disorders, skin inflammation and ringworm all can make hair fall out. A condition called telogen effluvium causes more hair than usual to shed but does not lead to baldness.